1. Field
Apparatuses, devices, and articles of manufacture consistent with the present disclosure relate to analog-to-digital conversion in image sensors and, in particular, to controlling whether to attenuate an input signal according to a size of an input signal when performing the analog-to-digital conversion.
2. Description of the Related Art
A complementary metal-oxide-semiconductor (CMOS) image sensor is a solid-state image pickup device manufactured using CMOS processes. A CMOS image sensor is manufactured at lower cost and has pixels that are smaller in size than a charge-coupled device (CCD) image sensor including a high-voltage analog circuit. With the increase of performance of a CMOS image sensor, it has been widely used in electronic appliances including a portable device such as a smart phone or a digital camera.
A pixel array included in a related art CMOS image sensor includes a photoelectric conversion element in each pixel. The photoelectric conversion element generates an electrical signal varying with the quantity of incident light and the CMOS image sensor processes the electrical signal to generate an image. During this process, the electrical signal is analog-to-digital converted. As a number of pixels increases as the resolution and speed of the image sensor increases, there is a disadvantage in that the performance degrades and power consumption increases for high-resolution, high-speed image sensors.